Xx. Cheng et al., CHARACTERIZATION OF THE GENE FOR AN IMMUNODOMINANT 72 KDA LIPOPROTEINOF MYCOPLASMA-MYCOIDES SUBSP MYCOIDES SMALL COLONY TYPE, Microbiology, 142, 1996, pp. 3515-3524
With the aim of characterizing specific immunogenic proteins of Mycopl
asma mycoides subsp, mycoides small colony (SC) type, the aetiological
agent of contagious bovine pleuropneumonia, a gene encoding a major i
mmunogenic protein of 72 kDa named P72 was cloned and expressed in Esc
herichia coli. The expressed protein was of the same apparent molecula
r mass as that produced by the parent strain. The predicted molecular
mass of P72, based on the DNA-deduced amino acid sequence. was 61.118
kDa, significantly lower than the apparent molecular mass of endogenou
s or recombinant P72 on SDS-PAGE. Analysis of the amino acid sequence
revealed a typical prokaryotic signal peptidase II - membrane lipoprot
ein lipid attachment site and a transmembrane structure domain in the
leader sequence at the aminoterminal end of the protein. P72 was shown
to be a lipoprotein and its surface location was confirmed by trypsin
treatment of whole cells. An unassigned gene encoding a peptide with
some similarity to P72 was found on the genome sequence of M. capricol
um subsp. capricolum but not on that of Mycoplasma genitalium. The P72
gene was detected in 11/11 M. mycoides subsp. mycoides SC strains. An
tiserum against recombinant P72 reacted strongly with 12/12 strains of
M. mycoides subsp. mycoides SC, weakly with Mycoplasma bovine group 7
strain PG50, but not with other members of the 'mycoides cluster' or
closely related mycoplasmas. Cows experimentally contact-infected with
M. mycoides subsp. mycoides SC developed a humoral response against P
72 within 35 d. P72 is a specific antigenic membrane lipoprotein of M.
mycoides subsp. mycoides SC with potential for use in development of
diagnostic reagents. It seems to belong to a family of lipoproteins of
the 'mycoides cluster'.